Ultrahigh-Sensitivity Pressure and Vibration Sensor

A novel new ultrahigh-sensitivity pressure and vibration sensor is introduced. The sensor is based on the concept of using a variable ultracapacitor rather than a variable capacitor as a transduction mechanism. The variable ultracapacitor assembly consists of two electrodes on which carbon nano-tubes of a length of 20 μm are grown. One electrode is fixed and is fully immersed in the electrolyte, while the other electrode is movable and is positioned outside of the electrolyte. In response to pressure or vibration, an extremely small displacement of 20 μm (less than the width of a human hair) submerges the movable electrode into the electrolyte and results in a substantially large variation in capacitance (from zero to 54 μF in the present prototype).